1. Field of the Invention
The invention relates in general to a method of compensating a zipper image, and more particularly, to a method of compensating a zipper image by using K-value and a method to calculate the K-value.
2. Description of the Related Art
FIG. 1 shows a staggered charge coupled device (CCD) of a scanner 100. As shown in FIG. 1, the scanner 100 is connected to a host computer 150. The scanner 100 includes a staggered CCD 110 that has one primary line and one secondary line for each color, an application specific integrated circuit (ASIC) 120, an image compensation buffer 130, and an I/O interface 140. Before scanning, the scanner 100 performs an image compensation operation so that an image compensation parameter is obtained and saved in the host computer 150.
When the staggered CCD 110 scans any part of a document, an image compensation parameter related to this part is retrieved from the host computer 150, and transmitted to the image compensation buffer 130 via the I/O interface 140. The intermittently scanned image scanned by the staggered CCD 110 is then corrected by the ASIC 120 according to the image compensation parameter transmitted from the image compensation buffer 130. The corrected image is then transmitted to the host computer for storage via the I/O interface 140.
When the staggered CCD scans an image, if the line distance between the primary line and the secondary line is short, the primary line is inevitably affected by the light reflected from the secondary line. Similarly, the light reflected from the primary line vice versa also affects the secondary line. The fidelity of the document (as shown in FIG. 2) is easily deteriorated. Further, after scanning with a staggered CCD, a so-called zipper image (as shown in FIG. 3) is likely to occur. The zipper image is more significant for a document having a black-and-white boundary. Such zipper image causes errors for image scanning. Currently, no answer for resolving the zipper image has been disclosed yet.